Conventional acoustic wave sensor performs acoustic wave sensing by PZT (piezoelectric). Electric charge transfer in PZT makes partial electric charges distributing non-uniformly to generate electric potential difference when acoustic wave causes deformation of PZT. PZT acoustic wave sensor performs acoustic wave sensing by electric potential difference. However, PZT acoustic wave sensor merely detects small range of acoustic wave frequency (approximately 140 kHz), and the direction of acoustic wave is constrained as well.